Automatic diaphragm



Aug. 31, 1937.

O. RISZDORFER AUTOMATIC DIAPHRAGM Original Filed July 18, 1952 2 Sheets-Sheet l 1937- o. RISZDORFER I ,881

AUTOMATIC DIAPHRAGM Original Filed July 18, 1952 2 Sheets-Sheet 2 Patented Aug. 31, 1937 PATENT OFFlCE AUTOMATIC DIAPHRAGM fidiin Riszdorfer, Budapest, Hungary Original application July 18, 1932, Serial No.

623,216. Divided and this application August 6, 1935, Serial No. 34,967. In Hungary July 18,

8 Claims.

This invention relates to apparatus for varying the area of light apertures of photographic cameras in which apparatus the screening members defining the light apertures are moved by the influence of current of a photo-cell. The screening members are provided with openings and the said members are movably supported in order that when said members are moved relative to each other, the said openings may be brought more or less into registry in order that the light apertures may be regulated to include the full area of both of the apertures when they are alined, or restricted in area if the members are adjusted so that only portions of the light openings are in registry or alinement.

The subject matter of this application is divided from my application filed July 18, 1932,

Serial Number 623,216, patented September 3,

It is an object of this invention to support or suspend screening members in operative relation to an object lens of a photographic camera and to provide means operated by a current of a photo-cell for moving the said members relatively, in order that openings in the said members will be brought to a greater or less degree into alinement with each other in order that light passing therethrough may be received by the lens.

A further object of the invention is to maintain the members so that the light aperture is permanently kept in the optical axis and it is immaterial from the point of view of the invention whether the diaphragm is placed in front of the object lens, behind the object lens, or between the individual lenses forming the object lens and the screeningelements may be provided in such members as warranted by the conditions.

With the foregoing and other objects in view, the invention consists in the details of construction, and in the arrangement and combination of parts to be hereinafter more fully set forth and claimed.

In describing the invention in detail, reference will be had to the accompanying drawings formyieldingly ing part of this application, wherein like characters denote corresponding parts in the several views, and in which- Figure 1 is a front view of one type of diaphragm embodying the invention, composed of diaphragm elements operated by means of a cord drivefrom a shaft common to the 'said elements;

Figure 2 is an edge view thereof with the lenses in section, omitting the shaft bearing;

magnet itself is not shown on Figure 3 is a front view of the diaphragm and its operating mechanism, modified as compared with the construction of. Figure l in which a gear wheel and perforated strip are employed for operating the diaphragm;

Figure 4 is an edge view thereof, omitting the bearings for the shaft;

Figure 5 is a modification of means for mounting and operating the diaphragm in which an adjustable shaft and cord drive are included;

Figure 6 is an edge view thereof with the bearings of the shafts omitted and with the lens in section;

Figure 7 illustrates a further modified construction embodying the invention including the 15 means for balancing one of the shafts;

Figure 8 is an edge view thereof omitting the bearings for the shafts.

In the arrangement shown in Figures 1 and 2, the screening elements consist of two plates 3| 20 and 32, the said plates being located in mutually parallel planes, and actuated to perform rectilinear movements, openings 33 and 34 of closed shape and mutually equal size being provided, one-in each of said plates. These screening ele- 25 ments 3| and 32, actuated so as to move, for instance, between the two halves 33 and 34 of the object lens, have been attached to the fixed part of the photographic camera by means of the springs 35, 36 and 31, 38, respectively; the bottom ends of the plates are mutually connected by means of the cord 39. This c'ord may preferably be made of.silk or the like. In order to insure the proper tensioned condition of the cord 39, the latter has been wound around the rotatable shaft 40 arranged at right angles to the direction of. movement of the diaphragm elements. The shaft 40 carries arranged co-axially on it, the rotatable coil 4| of the magnet; the

the drawings. coil is fed by means of the current of a photocell C through conductors W. The shaft 40 is rotatable in the bearings 42 and 43. In the diaphragm elements, the openings 33 and 34 are arranged in such a manntir as to ensure that 45 as long as no current is flowing through coil 4|, the openings will mutually f er each other, that is to say th v espectively behind each opening there should stand that part 3 'of the other screen where the opening of the latter is located. If a current flows through coil 4|, this coil will deflect the shaft 40 team extent corresponding to the intensit I the current and the coil is fitted in such a manner that during this deflection the plates 31 and 32 should This 40 2 be mutually displaced in such manner that the openings should begin to overlap. The magni- .tude of cover will thus diminish in proportion with the intensity of the current flowing through 35 and 36 of. the diaphragm element moving downwards will become 'tensioned while the springs 31 and 38 of the other diaphragm ele-' ment will become slackened. Notably, in the case shown by way of example the openings 33 and 34 have been arranged so as to make one diagonal of each slot to be located in one and the same straight line corresponding to the direction of the relative movement of the diaphragms. By these means, it has been ensured that at every position of the elements, the diaphragm will give light apertures of mutually similar shape.

Instead of suspending the spring element on springs, it is possible to suspend them on cords in the manner shown in Figures 3 and 4. In this embodiment of the invention the diaphragm elements 46 and 41, which are similar to the diaphragm elements shown in Figures 1 and 2, are suspended on two flexible members or cords 44 and 45 running over are on the shaft 48, and the shaft is rotatably supported in bearings. On the bottom or lower edge of the diaphragm elements, the ends of a perforated strip 5| are attached to said elements and the perforations the teeth 52 of a gear wheel 54, which is moved by the oscillating coil 53 on the said shaft. The position of the coil 53 is controlled by current flowing from the photo-cell C over the conductors W connected to said coil. In other respects, the operation of the diaphragm members is similar to that of the operation of the members 3| and 32, Figures 1 and 2.

In order to adjust the tension of the flexible members or cord system for suspending and operating the diaphragm members,.provision may be made for such adjustment as embodied in the disclosure of Figures 5 and 6. In this form of the invention, provision is made for adjusting the shaft over which the suspending flexible members operate toward and away from the operative shaft which is-moved by the oscillating coil.. Referring specifically to Figures 5 and 6, 50 the suspending members 55 and 56 operate over a shaft 51. An adjusting screw 58 is threaded through a bracket having guides 59 and into the carrier 60 having hearings in which the'shaft 51 is rotatable. By adjusting the screw 58, the 55 carrier 60 is moved toward and away from'the shaft 60' having an oscillating coil 60 and by this means, the tensioning of theflexible members 55 and 55 is accomplished. The position of the coil 60" is controlled by current flowing from 60 the photo-cell C over the conductors W conncted to said coil. The shaft 50' is under the influence of an oscillating spring 62' which counter-acts the influence of bending stresses on the shaft. The arrangement of theadjustable-car- 65 rier for the shaft as disclosed-in Figures 5 and 6 may also be 'used for adjusting the tension of springs where the spring suspension such as shown in Figures 1 and 2 -is employed. While 70 it hasbeen stated that the adjustment of the carrier 60 with respect to the shaft 60' is in the direction of. movementof the diaphragms, it is not absolutely necessary that it should be adjusted in the said direction of-movement of the 75 diaphragms for as a matter of fact it is postions by means the coil 4|. During this movement, the springs the pulleys 49 and! which of the strip receive sible to deflect the cords 55 and 56 in other direcof guiding rollers.

In the case of the arrangement shown in Figures 5.and 6, where the shaft is influenced by the oscillating spring 62, the shaft is stressed 5 in one direction by the suspension described, and the shaft is subjected to bending stress. This stress increases the friction of the shaft in its bearings and the arrangement shown in Figures 7 and 8 has the purpose of reducing shaft friction. In this embodiment, the movement of the screen elements 63 and 64 takes place between V the parts 65 and 66 ofthe objective lens. The elements 63 and it are suspended from a shaft 61 by means of flexible elements or cords 68 and 69. On the lower edge of one of the screening elements, viz: of the screening element 64, thereis attached an extension 10 which is bent, outwardly and formed in U-shape, and it is in this outwardly bent part of the extension that the oscillating coil 1! moves. The position of the coil H is controlled by current flowing from the photo-cell C over the conductors W to the said coil. The lower end, or end portion, of the extension projects upward and flexible connections 13 and 14 have their ends connected to the extension 10 and to the screen elements 63, the said flexible members or cord's being wound around the shaft 12 in order that the screen elements may be moved by the rotation of the said shaft. A tensioning member such as a spring 15 is connected to the extension 10 and to a fixed portion of the photographing apparatus and is operative to exert a pull on the said extension 10. The spring tends to draw the screen element 64 downwardly and the spring tension is regulated in such a manner as to make the tensions of the part above the shaft and the partbelow the shaft of the flexible elements or cords 13-14 equal to prevent the shaft 12 from being subjected to any uni-lateral pull. It will be noted that in the drawings the diaphragms are spaced a considerable distance from each other. This has been done to more clearly disclose how the several parts operate and, as will be obvious, the two diaphragm members of each pair must, as in all photographic shutters, lie as close together as possible without the operation of sliding past one another being. prevented or retarded.

I claim:

1. In a photographic apparatus, a casing wherethrough a light beam may pass, a rotative electro-magnetic element journaled in the screens each having an opening therein, said screens extending across the beam path, flexible means connected to corresponding ends of said screens and passing around the rotary element whereby rotation of said element moves the screen openings into and out of registry, said electro-magnetic element being variably positioned on it 5 axis of rotation in accordance with the energization thereof, and means for energizing the winding including a photo-cell and conductive connections between the cell and winding. 2. In a photographic apparatus, a casing wherethrough a light beam may pass, a rotative electro-magnetic element journaled in the casing at one side of the beam path and ineluding a winding of conductive wire,.a pair of I screens each having an opening therein, said screens extending across the beam path, flexible 75 alight beam as electro-magnetie element to corresponding ends oi said screens and'passing around the rotaryeiement whereby rotation'oi' said element screen openinss'lnto'and out oi s st r. spring a 8 means urging the'screensraway frolnthe rotative meanswherebytomaintaintensiononthe flexibleel'ement, said element being variably positioned on ii: axis 01' rotation in accordance with the energization thereoi. and

the'beam-pathapairotscreens eaehhavingan opening therein, said screens extending-across the'beam'path, flexible means to cor-' responding ends of said screens and around the rotary element whereby rotation at i said element moves the screen openings into and out oi registry, and eiectro-magnetic means to vary the position of the rotary element and thereby control the extent of registration of the '25 said openings, said electro-magnetie means including arotafy magnetic member carrying'aaid rotary element, iixed poles-between'which lid rotary number is positioned, awinding for energising'said magnetic member, a photo-cell, and soconductive connections the cell and 4.In a photographic apparatus, 'i'caslng wherethrough a light beam may pass, a rotativeelement ,iournaied in the casing at one side of i thebeampath, apairoiscreenseachhavingan;

openingthereimsaidscreensextendingacrossthe beam path, flexible means connected to corresponding ends of said screens and passing around the rotary element whereby rotation of said element moves the screen openings into and out oi'- registry, spring mes-m. urging the screens away from the rotative means whereby to maintain tension on the flexible element, and electro-magnetic means to vary the position oi' the rotary Y element and thereby control the extent of registration of the said openings, said electro-magnetic means including a rotary magnetic member carrying said rotary element, iixed poles between which said rotary member is positioned, a winding-for energizing said magnetic member, a photo-cell, and conductivecon'nections between the cell and winding. a 5. Ina photographic apparatus, a casing wherethrough a light beam may pass, a rotative eiectro-magnetic element journaled in the casing atone side of the beam path and including a winding of conductive wire, a pair of screens each having an opening therein, said screens extending across the beam path, flexible means connected to corresponding ends of said screens and passing around the rotary element whereby rotation of said element moves the screen openings into and out of registry, a-second rotary element on the side of the beam path opposite the flrst rotary element, a second flexible element connecting the remaining end of the screen and .passing around the'second rotary element, said electro-magnetic element being variably positioned on its axis of rotation in accordance with the ene'rgization thereof, and means for energizing the winding including a photo-cell and conductive connections, between the cell and winding.

6. In a photographic apparatus, a casing a .wherethroughalightbeammaypasaarotative-zpassing ,liielement-iournai'edinthecasingatonesideolm murotame inthccasandincluding tionedonitsaxisotrotatiminaocordance-with the energiaation tbereot;a.nd means ior enersizing the windim including a photo-cell and conductive an opaiing therein, said'screens extending across the beam flexible means connected to cor- 'rwondingendsoisaid screensandpassing around the rotary element whereby rotation of said element movesthe screen openings into and out-of reghtry, a second rotary element on the side ottheheam path opposite the first rotary elements second flexible element connecting the remainingendotthe screenandpassing around the second rotary element, and electro-magnetic means tovary the position of one of the rotary elements and thereby control the extent of regis tration of the. said openings, saideiectro-magnetic means including a rotary magnetic member carrying said rotary element, iixed' poles between which said rotary member is positioned, a winding for energizing said magnetic member, a photo-cell, and conductive connections between the cell and 8. In a ='photographic apparatus, acasing wherethrough a light beam may pass, a rotative element journaied in the casing at one side 01 thebeampath,apairoi'screenseachhavingan opening .therein, said screens extending across the beam path, flexible means connected to corresponding ends of said screens and passing around the rotary element whereby rotation of said element moves the screen openings into and out of registry, is second rotary element on the side of the beam path opposite the first rotary element,

a second flexible element connecting the remainingendoithescreenandpassingaroundthe second rotary element, one of said flexible elements constituting ,a sprocket chain and the rotary element where'on it engages being a sprocket meshing with said chain, and magnetic means to vary the position of one of the rotary elements and thereby control the extent oi registration of the said openings, said electro-magnetic means including arotary magnetic member carrying said rotary element, fixed poles between which said rotary member is posi-' tioned, a winding for energizing said magnetic member, a photo-cell, and conductive connections between the cell and winding. 

